Method and apparatus for collapsing the countersink wall of a can end



Z7 ZJE Hllllllll Jan. 25, 1955 2,700,355

G. C. ERB METHOD AND APPARATUS FOR COLLAPSING THE COUNTERSINK WALL OF A CAN END Filed NOV. 10, 1949 I 2 Sheets-Sheet l mmvrox 62m. A 5:4 M

2 Sheets-Sheet 2 METHOD C Filed Nov. 10, 1949 Jan. 25, 1955 Z Illlln M GEOEQE c. figfflji BY M we? JAM & flnmfi f A TTOENEYS United States Patent METHOD AND APPARATUS FOR COLLAPSING THE COUNTERSINK WALL OF A CAN END George C. Erb, deceased, late of Flushing, N. Y., by Annie B. Erb, executrix, Flushing, N. Y., assignor to American Can Company, New York, N. Y., a corporation of New Jersey Application November 10, 1949, Serial No. 126,641

Claims. (Cl. 113-120) The present invention relates to a method of and apparatus for collapsing the countersink wall of a countersunk can end which is seamed onto a can body, thereby gaining certain novel advantages. 7

In order to securely attach a can end to a can body, seaming instrumentalities, such as seaming rolls or seaming dies, are employed to interlock adjacent marginal or flange portions of the can body and end to form an end seam, usually a double seam. To accomplish this seaming operation, it is the customary practice to employ a chuck or plate to back up or support these marginal portions against the pressure of the seaming instrumentalities as they are formed into the seam. In order to accommodate the chuck, the can end must be deeply countersunk or recessed so that it extends down within the body, wall behind the seam. This results in the finished container having a dished, recessed end which readily catches dirt and dust particles and/or liquids. Then too, the resultant container has less capacity than it otherwise would have if the end were not recessed.

By utilizing the present invention to collapse, upset or reshape the countersink wall of the can end after the seam has been so formed, it is possible to eliminate the end recess or to reduce its depth.

An object of the present invention is to provide a method of and apparatus for transforming a conventional countersunk container end into an end which is substantially flush with the top of the container to produce a smooth top container of pleasing appearance.

Another object is the provision of a method and appa-, ratus for moving the countersunk end panel of a container axially away from the center of the container to thereby increase the capacity of the container, the movement of the end panel being accompanied by a reshaping of the vertical countersink wall. 1

A further object is the provision of a method of and apparatus for reforming a substantially straight countersink end wall into a folded condition thereby providing a shoulder which overhangs an end panel section to thereby secure a separate part, plate or member to the container.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure l is a cross-sectional view through a collapsing mechanism embodying the present invention, and for use in carrying out the method steps of the invention, the view showing a can in place in the mechanism;

Fig. 2 is an enlarged sectional detail illustrating the position of the main parts of the mechanism of Fig. l at an early stage in the collapsing operation;

Figs. 3, 4 and 5 are views similar to Fig. 2 showing the position of the parts at advancing stages;

Fig. 6 is a view similar to Fig. 2 showing the completion of the collapsing operation;

Fig. 7 is a view similar to Fig.2 but showing a modified form of the collapsing mechanism at the beginning of the collapsing operation;

Fig. 8 is a view showing the position of the mechanism ofdFig. 7 at the completion of the collapsing operation; an

Figs. 9 and 10 are sectional details similar to Figs. 7 and 8 showing how the instant invention can be used to secure a separate member to the end of a container.

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which is joined to the panel 13 by curved wall section 15.

The end 12 is secured to the can body 11 by means of a double seam 16 which includes the countersink wall 14 as its inner layer and which is formed in the usual manner by means of a conventional type of seaming mechanism as illustrated in United States Patent 1,699,069 issued January 15, 1929, to Felix Huntar on Can Double Seaming Machine. The countersink wall 14 is joined to the top of the outer layer of the double seam 16 in a curved section 17, which has a smaller radius of curvature than the curved section 15 (Figs. 1, 2 and 3).

As illustrated in this Huntar patent, the interfolded double seam 16 is formed by means of forming rolls which exert a radial pressure toward the axis of the can as the seam is being formed. In order to properly form the double seam, the backing up plate or chuck must extend downwardly behind the end seam for at least the full depth of the seam. It is for this reason that the end member 12 of Fig. l is formed initially with a comparatively deep countersink wall 14.

A deeply recessed end, however, has several disadvantages as hereinbefore explained.

The present invention overcomes these disadvantages by providing a practical method and apparatus for collapsing or reshaping the countersink wall 14, thus raising the end panel portion 13 and eliminating or reducing the end recess.

As a result of the collapsing operation, the contour of the end member 12 of the can 10 is changed from that of Fig. 2, wherein a deep vertical countersink wall 14 exists, to that of Fig. 6, where the vertical wall 14 is eliminated, and a substantially horizontal triple fold 18 of metal is produced around the marginal portion of the end panel 13. This transition is accomplished by first reforming the vertical wall 14 into an inwardly extending shoulder 19 (Figs. 4 and. 5) and then flattening the shoulder against the end panel 13.

Anexemplary form of apparatus for effecting this collapsing operation is illustrated in Fig. l. The parts illustrated in this figure are well adapted for mounting in a conventional reciprocating press and include a stationary inside block or mandrel 20 which may be mounted in the bed of a press and over which the can 10 is placed. The block 20 has the same cross-sectional shape as the can body 11 and fits snugly within the body with its upper face contacting the inside surface of the end panel 13. In order to minimize friction as the body 11 is slid on and off, the lower part of the block 20 is slightly reduced as at 21.

The marginal edge portion of the upper surface of the block 20 is ground off or recessed to a depth substantially equal to two thicknesses of the material of the end 12 to form an offset 22. The reason for this, as will be made more fully apparent hereinafter, is to finally form the panel 13 flush with the upper layer of the triple fold 18.

When the can 10 has been positioned over the block 20, the movable parts of the collapsing mechanism are moved downwardly against the end 12 of the can 10. These movable parts comprise what may be termed a collapsing head 23 and include a hollow holder member 24 which may be attached to the movable slide of a press by means of a shank 25. The holder 24 carries an annular supporting and collapsing ring 26, secured thereto by means of screws 27, one of which is shown in Fig. 1.

As the collapsing head 23 is moved toward the can end 12, the double seam 16 enters an annular recess 28 formed in the lower inside portion of the ring 26. The recess 28 is formed with a straight or flat upper wall or die surface 29 and a side wall 30, which are connected by a curved wall section 31. The curved section 31 and the upper portion of the side wall 30 are complementary in shape to the upper outside portion of the double seam 16 in order that the seam may fit snugly within the recess 28 and be supported against lateral movement. herecess 28 preferably has a height equal to at least the he ght of the seam 16 and a width equal to at least the Width of the seam 16 plus the width of the triple fold section 18.

Before the seam 16 fully enters the recess 28, the upper surface of the end panel 13 is engaged by a clamping block or pad 32 which clamps it against the inside block 20 and prevents it from buckling during the ensu ng collapsing operation. The clamping pad 32 is held 111 place Within the hollow holder 24 and the ring 26 by means of a shoulder 33 which engages the inside upper corner of the ring 26. The clamping pressure is created by strong compression springs 34 which back up the pad 32 and are maintained in place in aligned spring pocket-s 35 and 36, bored in the holder 24 and the pad 32 respectively.

After the seam 16 is fully seated in the recess 28, as shown in Fig. 2, the continued movement of the collapsing head 23 exerts a lengthwise or axial pressure against the top of the seam 16, which pressure is transmitted to the countersink wall 14 and causes the outer marginal or peripheral portion of the end panel 13 to bend until t contacts the surface of the offset 22 (Fig. 3). It is this portion of the panel 13 that becomes the lower fold of the triple fold 18. As the head 23 continues its downward movement and exerts continued pressure against the end seam 16, thus forcing it and the body 11 downwardly with respect to the end panel 13, the radius of curvature of the curved wall section 15 decreases progressively until it becomes smaller than the radius of curvature of the curved wall section 17. When this condition is reached the metal in the upper portion of the countersink wall 14 which includes the curved section 17, is forced against the upper wall or die surface 29 of the recess 28 and moves or rolls progressively inwardly along the die surface 29 away from the double seam 16 (Figs. 4 and 5).

The upper portion of the countersink wall 14, which is to become the upper layer of the triple told 18, thus assumes a horizontal position along the die surface 29. This progressive movement of the upper portion of the countersink wall 14 causes the lower portion of the countersink wall 14, which is to become the middle layer of the triple fold 18, to pull away from the double seam 16.

Thus, the vertical countersink wall 14 is reshaped into the inwardly extending shoulder 19 (Figs. 4, 5 and 6) which is hollow until it is finally flattened against the peripheral portion of the end panel 13 to create the triple fold 18 (Fig. 6).

During this collapsing operation, the relative positions of the end panel 13 and the double seam 16 constantly change and the panel 13 approaches the level of the top of the seam 16. In effect, the panel 13 is raised or moved axially away from the center of the can 10, although actually in the illustrated embodiment of the invention the panel 13 remains stationary while the rest of the can moves.

Fig. 6 illustrates the position of the various parts of the collapsing apparatus and the final shape of the Wall 14 at the completion of the collapsing operation. It can be seen that the triple told 18 has been received in the offset 22. Since the offset 22 has a depth equal to that of the two lower layers of the triple fold 18, the upper layer of the told 18 and the panel 13 are coplanar and a smooth, substantially unindented surface which is flush with the top of the end seam 16 is produced.

Simultaneously with the collapsing operation described above, an outward component of the axially applied collapsing pressure forces the curved wall section at the lower end of the countersink wall outwardly so that it is at all times tightly pressed against the inner wall of the can body 11. As this tight engagement continues after the operation is completed, the collapsed wall serves as an annular truss or support for the end seam.

After completion of the collapsing operation, the collap-sing head 23 is moved upwardly a suflicient distance to permit the can 10 to be stripped off the block by a stripper ring 37, which is actuated by any suitable mechanism. The can does not remain in the head 23 since the clamping pad 32 acts as a knockout pad.

It will be obvious that, if desired, the block 20 may be made movable and the collapsing head 23 may be stationary, or both the block 2t) and the head 23 may be oppositely movable. It is also possible to mount and operate the collapsing mechanism in a horizontal position.

A slightly modified "form of the instant invention is illustrated in Figs. 7 and 8. In this embodiment, the offset 22 in the inside block 20 is omitted. The collapsing operation on the counter-sink wall 14 is substantially the same as has been hereinbefore described, but the omission of the ofiset 22 results in a reformed can 10 wherein the main end panel 13 is in the same plane as the lower layer of the triple fold 18 instead of being coplanar with the upper layer.

Figs. 9 and 10 illustrate a modified embodiment wherein the instant invention is utilized to attach a separate member or plate 38 to the end of the can. The member 38 which may 'be made of fibre, metal, plastic or any other suitable material, is placed upon the end panel 13 prior to or at the time the can 10 is positioned over the inside block 20. The collapsing head 23 is then moved downwardly to collapse the countersink wall 14 as previously described. This results in the countersink wall 14 being reformed into the shoulder 19 (Fig. 10) which overhangs the peripheral portion of the member 38 and prevents its removal from the can 10. If the member 38 is to be movable with respect to the can end panel 13, as would be necessary if it were a rotatable or slidable sifter dredge, the downward movement of the head 23 is stopped before the plate is tightly clamped in position. Fig. 10 shows the final position of the collapsing apparatus when the member 38 is to be movably attached to the can. It will be noted that the shoulder 19 engages the upper marginal edge of the member 38 merely in a light frictional line contact, which prevents axial movement of the member 38 and yet permits it to slide easily over the end panel 13.

If the member 38 is to be immovably attached to the can, the collapsing head is lowered further to more fully collapse the shoulder 19 against the periphery of the member 38 and thus clamp the member in position.

Obviously, the member 38 need not be a flat plate. Its center portion may be domed or given any suitable configuration and its marginal edge portion may be bent, hemmed or curled either upwardly or downwardly, as desired.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of parts of the apparatus mentioned herein and in the steps and their order of accomplishment of the method described herein, without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the apparatus and method hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. The method of collapsing the countersink wall of an upstanding end seam such as a double seam wherein said countersink wall extends downwardly inside of an end seam and merges into an end panel, comprising clampmg said end panel, closely confining said end seam against outward radial movement, positioning said end seam agalnst an inwardly extending die surface, subjecting said countersink wall to axial pressure to progressively force the upper portion of said wall into contact with said inwardly extending die surface to reshape said countersink wall into an inwardly extending hollow shoulder, flattening said hollow shoulder against said end panel to form a triple fold around the periphery of said end panel, and making said end panel and the upper layer of said triple fold substantially coplanar to form a smooth end surface.

2. The method of securing a member to a can wherein a countersink wall extends downwardly inside of an upstanding end seam such as a double seam and merges into an end panel, comprising placing said member against said end panel, clamping said member and said end panel together, closely confining said end seam, including said countersink wall, against outward radial and axial movement, positioning said end seam against an inwardly ex tending die surface, and subjecting said countersink wall to axial pressure to progressively force the upper portion of said wall into contact with said inwardly extending die surface to reshape said Wall into an inwardly extending shoulder which overhangs and secures said member.

3. In the production of substantially flat top cans wherein the closure of each can is secured to the can body in an upstanding end seam such as a double seam and the countersink wall surrounding the closure panel is in close contact with the interior of the can body wall,

the method comprising uniting said end closure with said body in an upstanding end seam such as a double seam, closely confining said end seam and countersink wall against outward radial movement, providing a substantially flat confining surface in the plane of the top of said end seam and countersink wall, and subjecting said countersink wall to axial pressure directed toward said confining surface to collapse said countersink wall axially and inwardly along said flat confining surface while the lower end of said wall is at all times tightly pressed against the inner wall of the can body so that said countersink wall is substantially flattened with the marginal portion of said panel to form a triple fold annular truss for said end seam and to provide a substantially fiat top container with increased volume.

4. In apparatus for producing a substantially flat top can from a can body having an end memberunited thereto in an upstanding end seam such as a double seam, the mechanism comprising a mandrel conforming substantially to the internal transverse dimensions of the can body and having a substantially fiat upper marginal portion for supporting the panel of the can end member and the lower end of the radially innermost layer of the upstanding end seam which unites said body and end member, a die having a substantially cylindrical surface surrounding and contacting the outer layer of said seam and a substantially fiat surface co-planar with and engaging the top of said end seam so that said cylindrical and flat die surfaces confine the upper and outer surfaces of said end seam against outward radial and axial movement, a yieldable clamping block in said die for clamping said end member panel against said flat portion of the mandrel, said block having a cylindrical surface spaced radially inwardly from said cylindrical surface of the die as close as possible by a distance not less than the sum of the thickness and half the height of said end seam, said fiat surface of the die and said cylindrical surfaces of the die and block defining an annular recess in the die, means for moving said mandrel and die relatively toward each other to collapse said innermost layer of the seam axially and inwardly along said fiat die surface in said annular recess while the lower end of said innermost layer is at all times tightly pressed against the inner wall of the can body so that said innermost layer of the seam is collapsed against the peripheral margin of said end member panel to form with said panel margin a triple fold annular truss for said end seam and to provide a substantially flat top container with increased volume.

5. In apparatus for producing a substantially flat top can from a can body having an end member united thereto in an upstanding end seam such as a double seam, the mechanism comprlsmg a mandrel conforming substantially to the internal transverse dimensions of the can body for supporting the central portion of the panel of the can end member and the lower end of the radially innermost layer of the upstanding end seam which unites said body and end member, the upper surface of said mandrel being substantially flat and having a marginal edge portion recessed to a depth equal to substantially two thicknesses of the closure material, a die having a substantially cylindrical surface surrounding and contacting the outer layer of said seam and a substantially flat surface co-planar with and engaging the top of said end seam so that said cylindrical and flat die surfaces confine the upper and outer surfaces of said end seam against outward radial and axial movement, a yieldable clamping block in said die for clamping said end member panel against said flat portion of the mandrel, said block having a cylindrical surface spaced radially inwardly from said cylindrical surface of the die by a distance not less than the sum of the thickness and half the height of said end seam, said flat surface of the die and said cylindrical surfaces of the die and block defining an annular recess in the die, means for moving said mandrel and die relatively toward each other to raise the central portion of said panel to substantially flush with the top of said end seam and to collapse said innermost layer of the seam axially and inwardly along said flat die surface in said annular recess while the lower end of said innermost layer is at all times tightly pressed against the inner wall of the can body so that said innermost layer of the seam is collapsed and substantially flattened against the peripheral margin of said end member panel to form with said panel margin a triple fold annular truss for said end seam and to provide a substantially fiat top container with increased volume.

References Cited in the file of this patent UNITED STATES PATENTS 660,730 Miller Oct. 30, 1900 782,142 Kenny Feb. 7, 1905 1,388,888 Pomeon Aug. 30, 1921 1,590,749 Hulbert June 29, 1926 1,590,754 Hulbert June 29, 1926 1,607,923 Sebell Nov. 23, 1926 1,719,512 Krembs July 2, 1929 1,803,616 Hothersall May 5, 1931 2,006,691 Giesler July 2, 1935 2,017,460 Hothersall Oct. 15, 1935 2,106,020 Schmidtke Jan. 18, 1938 2,119,630 Williams June 7, 1938 2,162,731 Lyon June 20, 1939 

